- Heat a large skillet over medium-high heat. Add 2 teaspoons oil to pan; swirl to coat. Sprinkle chicken evenly with 1 teaspoon salt and 1 teaspoon pepper.
- Add chicken to pan; cook 4 minutes on each side or until chicken is done. Remove from pan.
- Combine broth and mustard, stirring with a whisk.
- Add remaining 1 tablespoon oil to pan; swirl. Add remaining 1 teaspoon salt, remaining 1 teaspoon pepper, sage, rosemary, apple, Brussels Sprouts and onion to pan; cook 4 minutes, stirring occasionally.
- Stir in broth mixture.
- Return chicken to pan; cook 3 minutes or until liquid is reduced by half.